A cooperation-based approach to energy optimization in wireless ad hoc networks

A well known and still open issue for wireless ad hoc networks is the unfair energy consumption among the nodes. The specific position of certain nodes composing an ad hoc network makes them more involved in network operations than others, causing a faster drain of their energy. To better distribute the energy level and increase the lifetime of the whole network, we propose to periodically force the cooperation of less cooperative nodes while overwhelmed ones deliberately stop their service. A dedicated ad hoc network routing protocol is introduced to discover alternative paths without degradation in the overall network performance

CAM04-1: Admission control in self aware networks

The worldwide growth in broadband access and multimedia traffic has led to an increasing need for Quality- of-Service (QoS) in networks. Real time network applications require a stable, reliable, and predictable network that will guarantee packet delivery under QoS constraints. Network self- awareness through on-line measurement and adaptivity in response to user needs is one way to advance user QoS when overall network conditions can change, while admission control (AC) is an approach that has been commonly used to reduce traffic congestion and to satisfy users' QoS requests. The purpose of this paper is to describe a novel measurement-based admission control algorithm which bases its decision on different QoS metrics that users can specify. The self-observation and self- awareness capabilities of the network are exploited to collect data that allows an AC algorithm to decide whether to admit users based on their QoS needs, and the QoS impact they will have on other users. The approach we propose finds whether feasible paths exist for the projected incoming traffic, and estimates the impact that the newly accepted traffic will have on the QoS of pre-existing connections. The AC decision is then taken based on the outcome of this analysis

Sol-gel derived mesoporous Pt and Cr-doped WO(3) thin films: the role played by mesoporosity and metal doping in enhancing the gas sensing properties

Mesoporous Cr or Pt-doped WO(3) thin films to be employed as ammonia gas sensors were prepared by a fast one-step sol-gel procedure, based on the use of triblock copolymer as templating agent. The obtained films were constituted by aggregates of interconnected WO(3) nanocrystals (20-50 nm) separated by mesopores with dimensions ranging between 2 and 15 nm. The doping metals, Pt and Cr, resulted differently hosted in the WO(3) mesoporous matrix. Chromium is homogeneously dispersed in the oxide matrix, mainly as Cr(III) and Cr(V) centers, as revealed by EPR spectroscopy; instead platinum segregated as Pt (0) nanoparticles (4 nm) mainly included inside the WO(3) nanocrystals. The semiconductor layers containing Pt nanoclusters revealed, upon exposure to NH(3), remarkable electrical responses, much higher than Cr-doped and undoped layers, particularly at low ammonia concentration (6.2 ppm). This behavior was attributed to the presence of Pt nanoparticles segregated inside the semiconductor matrix, which act as catalysts of the N-H bond cleavage, decreasing the activation barrier in the ammonia dissociation. The role of the mesoporous structure in influencing the chemisorption and the gas diffusion in the WO(3) matrix appeared less decisive than the electronic differences between the two examined doping metals. The overall results suggest that a careful combination between mesoporous architecture and metal doping can really promote the electrical response of WO(3) toward ammonia

A Novel DLG1 Variant in a Family with Brugada Syndrome: Clinical Characteristics and In Silico Analysis

Background: Brugada syndrome (BrS) is an inherited primary channelopathy syndrome associated to sudden cardiac death. Overall, variants have been identified in eighteen genes encoding for ion channel subunits and seven genes for regulatory proteins. Recently, a missense variant in DLG1 has been found within a BrS phenotype-positive patient. DLG1 encodes for synapse associated protein 97 (SAP97), a protein characterized by the presence of multiple domains for protein–protein interactions including PDZ domains. In cardiomyocytes, SAP97 interacts with Nav1.5, a PDZ binding motif of SCN5A and others potassium channel subunits. Aim of the Study: To characterize the phenotype of an Italian family with BrS syndrome carrying a DLG1 variant. Methods: Clinical and genetic investigations were performed. Genetic testing was performed with whole-exome sequencing (WES) using the Illumina platform. According to the standard protocol, a variant found by WES was confirmed in all members of the family by bi-directional capillary Sanger resequencing. The effect of the variant was investigated by using in silico prediction of pathogenicity. Results: The index case was a 74-year-old man with spontaneous type 1 BrS ECG pattern that experienced syncope and underwent ICD implantation. WES of the index case, performed assuming a dominant mode of inheritance, identified a heterozygous variant, c.1556G>A (p.R519H), in the exon 15 of the DLG1 gene. In the pedigree investigation, 6 out of 12 family members had the variant. Carriers of the gene variant all had BrS ECG type 1 drug induced and showed heterogeneous cardiac phenotypes with two patients experiencing syncope during exercise and fever, respectively. The amino acid residue #519 lies near a PDZ domain and in silico analysis suggested a causal role for the variant. Modelling of the resulting protein structure predicted that the variant disrupts an H-bond and a likelihood of being pathogenic. As a consequence, it is likely that a conformational change affects protein functionality and the modulating role on ion channels. Conclusions: A DLG1 gene variant identified was associated with BrS. The variant could modify the formation of multichannel protein complexes, affecting ion channels to specific compartments in cardiomyocytes

Intensity modulated radiotherapy in early stage Hodgkin lymphoma patients: Is it better than three dimensional conformal radiotherapy?

<p>Abstract</p> <p>Background</p> <p>Cure rate of early Hodgkin Lymphoma are high and avoidance of late toxicities is of paramount importance. This comparative study aims to assess the normal tissue sparing capability of intensity-modulated radiation therapy (IMRT) versus standard three-dimensional conformal radiotherapy (3D-CRT) in terms of dose-volume parameters and normal tissue complication probability (NTCP) for different organs at risk in supradiaphragmatic Hodgkin Lymphoma (HL) patients.</p> <p>Methods</p> <p>Ten HL patients were actually treated with 3D-CRT and all treatments were then re-planned with IMRT. Dose-volume parameters for thyroid, oesophagus, heart, coronary arteries, lung, spinal cord and breast were evaluated. Dose-volume histograms generated by TPS were analyzed to predict the NTCP for the considered organs at risk, according to different endpoints.</p> <p>Results</p> <p>Regarding dose-volume parameters no statistically significant differences were recorded for heart and origin of coronary arteries. We recorded statistically significant lower V30 with IMRT for oesophagus (6.42 vs 0.33, p = 0.02) and lungs (4.7 vs 0.1 p = 0.014 for the left lung and 2.59 vs 0.1 p = 0.017 for the right lung) and lower V20 for spinal cord (17.8 vs 7.2 p = 0.02). Moreover the maximum dose to the spinal cord was lower with IMRT (30.2 vs 19.9, p <0.001). Higher V10 with IMRT for thyroid (64.8 vs 95, p = 0.0019) and V5 for lungs (30.3 vs 44.8, p = 0.03, for right lung and 28.9 vs 48.1, p = 0.001 for left lung) were found, respectively. Higher V5 and V10 for breasts were found with IMRT (V5: 4.14 vs 20.6, p = 0.018 for left breast and 3.3 vs 17, p = 0.059 for right breast; V10: 2.5 vs 13.6 p = 0.035 for left breast and 1.7 vs 11, p = 0.07 for the right breast.) As for the NTCP, our data point out that IMRT is not always likely to significantly increase the NTCP to OARs.</p> <p>Conclusions</p> <p>In HL male patients IMRT seems feasible and accurate while for women HL patients IMRT should be used with caution.</p

A gate evaluation of the sources of error in quantitative 90Y PET

International audiencePurpose: Accurate reconstruction of the dose delivered by 90Y microspheres using a postembolization PET scan would permit the establishment of more accurate dose–response relationships for treatment of hepatocellular carcinoma with 90Y. However, the quality of the PET data obtained is compromised by several factors, including poor count statistics and a very high random fraction. This work uses Monte Carlo simulations to investigate what impact factors other than low count statistics have on the quantification of 90Y PET.Methods: PET acquisitions of two phantoms—a NEMA PET phantom and the NEMA IEC PET body phantom-containing either 90Y or 18F were simulated using GATE. Simulated projections were created with subsets of the simulation data allowing the contributions of random, scatter, and LSO background to be independently evaluated. The simulated projections were reconstructed using the commercial software for the simulated scanner, and the quantitative accuracy of the reconstructionand the contrast recovery of the reconstructed images were evaluated.Results: The quantitative accuracy of the 90Y reconstructions were not strongly influenced by the high random fraction present in the projection data, and the activity concentration was recovered to within 5% of the known value. The contrast recovery measured for simulated 90Y data was slightly poorer than that for simulated 18F data with similar count statistics. However, the degradation was not strongly linked to any particular factor. Using a more restricted energy range to reduce the randomfraction in the projections had no significant effect.Conclusions: Simulations of 90Y PET confirm that quantitative 90Y is achievable with the same approach as that used for 18F, and that there is likely very little margin for improvement by attempting to model aspects unique to 90Y, such as the much higher random fraction or the presence of bremsstrahlung in the singles data

Synthesis and Structure of Conjugated Molecules with the Benzofulvene Core

A general method to synthesize conjugated molecules with a benzofulvene core is reported. Up to four conjugated substituents have been introduced via a three-step sequence including (1) synthesis of 1,2-bis­(arylethynyl)­benzenes; (2) exo-dig electrophilic cyclization promoted by iodine; and (3) cross-coupling reaction of the resulting bis-iodobenzofulvenes with organoboron, organotin, or ethynyl derivatives under Pd catalysis. Structural aspects of the new compounds are discussed

Membrane-Assisted Charge Separation and Photocatalytic Activity in Embedded TiO2: A Kinetic and Mechanistic Study

TiO2 dispersed in polyester acrylate membranes was tested as a photocatalyst in the phenol mineralization reaction assisted by molecular oxygen. Kinetics experiments revealed that, although embedded, the oxide maintains significant catalytic activity. This result was first attributed to the homogeneous dispersion inside the polymeric host of TiO2 nanocrystals, which can be easily irradiated and interact with the reactants. Furthermore, the investigation of the photogenerated charge carriers in the photocatalyst demonstrated that electrons are trapped on Ti3+ centers, while holes are trapped on C-centered species of the polymer matrix. In the presence of O-2, the C-centered radicals of the polymer transform into peroxy radicals, reinforcing the charge separation in the polymer-embedded oxide with respect to the powder. The positive interference of the polymer matrix in reinforcing the electron hole separation is responsible for the relevant photoactivity of the embedded TiO2